oc cp returns "No such file or directory" for filenames with escape characters

[kgibm]

A pod took a core dump:

$ oc debug node/$NODE -t
[...]
# ls -l /host/var/lib/systemd/coredump/
total 115824
-rw-r-----+ 1 root root 118596950 Feb 28 16:25 'core.Default\x20Executo.1001210000.06a2f2e0997c46b2b50bdac3c25ab072.831941.1677601537000000.lz4'

Leave the debug pod up so that we can download the file through the debug pod:

# while true; do echo "hold this pod"; sleep 8; done

Find the debug pod:

$ oc get pods --field-selector=status.phase==Running --all-namespaces | grep debug
admin2-namespace   worker1-debug       1/1     Running   0    3m54s

Downloading the core dump directory works although with a strange directory structure:

$ oc cp --namespace admin2-namespace worker1-debug:/host/var/lib/systemd/coredump/ coredumps
tar: Removing leading `/' from member names
$ tree coredumps 
coredumps
└── core.Default
    └── x20Executo.1001210000.06a2f2e0997c46b2b50bdac3c25ab072.831941.1677601537000000.lz4

However, downloading the file fails trying with various quoting and escape (client is macOS but same problem on Windows):

1. No quoting:

   $ oc cp --namespace admin2-namespace worker1-debug:/host/var/lib/systemd/coredump/core.Default\x20Executo.1001210000.06a2f2e0997c46b2b50bdac3c25ab072.831941.1677601537000000.lz4 core.dmp.lz4
   tar: Removing leading `/' from member names
   tar: /host/var/lib/systemd/coredump/core.Defaultx20Executo.1001210000.06a2f2e0997c46b2b50bdac3c25ab072.831941.1677601537000000.lz4: Cannot stat: No such file or directory
   tar: Exiting with failure status due to previous errors
   

2. Single quoting:

   $ oc cp --namespace admin2-namespace 'worker1-debug:/host/var/lib/systemd/coredump/core.Default\x20Executo.1001210000.06a2f2e0997c46b2b50bdac3c25ab072.831941.1677601537000000.lz4' core.dmp.lz4
   tar: Removing leading `/' from member names
   tar: /host/var/lib/systemd/coredump/core.Default/x20Executo.1001210000.06a2f2e0997c46b2b50bdac3c25ab072.831941.1677601537000000.lz4: Cannot stat: No such file or directory
   tar: Exiting with failure status due to previous errors
   

3. Single quoting and converting \x20 to a space:

   $ oc cp --namespace admin2-namespace 'worker1-debug:/host/var/lib/systemd/coredump/core.Default Executo.1001210000.06a2f2e0997c46b2b50bdac3c25ab072.831941.1677601537000000.lz4' core.dmp.lz4
   tar: Removing leading `/' from member names
   tar: /host/var/lib/systemd/coredump/core.Default Executo.1001210000.06a2f2e0997c46b2b50bdac3c25ab072.831941.1677601537000000.lz4: Cannot stat: No such file or directory
   tar: Exiting with failure status due to previous errors
   

4. Trying a wildcard:

   $ oc cp --namespace admin2-namespace 'worker1-debug:/host/var/lib/systemd/coredump/core.Default*.06a2f2e0997c46b2b50bdac3c25ab072.831941.1677601537000000.lz4' core.lz4
   tar: Removing leading `/' from member names
   tar: /host/var/lib/systemd/coredump/core.Default*.06a2f2e0997c46b2b50bdac3c25ab072.831941.1677601537000000.lz4: Cannot stat: No such file or directory
   tar: Exiting with failure status due to previous errors
   

5. Double quotes doesn't return an error but doesn't download the file:

   $ oc cp --namespace admin2-namespace "worker1-debug:/host/var/lib/systemd/coredump/core.Default\x20Executo.1001210000.06a2f2e0997c46b2b50bdac3c25ab072.831941.1677601537000000.lz4" core.dmp.lz4
   $ ls core.dmp.lz4
   ls: core.dmp.lz4: No such file or directory
   

Moving the file using the debug node works but isn't great because now utilities like coredumpctl think the core dump is gone:

Debug node:

$ mv '/host/var/lib/systemd/coredump/core.Default\x20Executo.1001210000.06a2f2e0997c46b2b50bdac3c25ab072.831941.1677601537000000.lz4' '/host/var/lib/systemd/coredump/core.DefaultExecuto.1001210000.06a2f2e0997c46b2b50bdac3c25ab072.831941.1677601537000000.lz4'

Client:

$ oc cp --namespace admin2-namespace 'worker1-debug:/host/var/lib/systemd/coredump/core.DefaultExecuto.1001210000.06a2f2e0997c46b2b50bdac3c25ab072.831941.1677601537000000.lz4' core.dmp.lz4 
tar: Removing leading `/' from member names
$ ls -l core.dmp.lz4
-rw-r--r--  1 kevin  wheel  118596950 Feb 28 13:29 core.dmp.lz4

oc version:

$ oc version
Client Version: 4.11.0-0.nightly-2022-05-18-171831
Kustomize Version: v4.5.4
Server Version: 4.11.21
Kubernetes Version: v1.24.6+5658434

[openshift-bot]

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[kgibm]

/lifecycle frozen

This is a continuing and significant impact, particularly for products that commonly have spaces in the thread name. This issue leads to complicated workarounds.